


Spilled Bath Water

by TotallyNotNerdy63



Category: Undertale (Video Game)
Genre: Biting, Cuddling & Snuggling, F/F, Female UnderFell Sans, Fluff, Fluff and Smut, Genderbending, Light Bondage, Other, Romantic Fluff, Smut, Underfell Sans (Undertale), Vaginal Fingering
Language: English
Status: Completed
Published: 2021-02-11
Updated: 2021-02-11
Packaged: 2021-03-17 21:08:41
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,273
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29357001
Author URL: https://archiveofourown.org/users/TotallyNotNerdy63/pseuds/TotallyNotNerdy63
Summary: Valentines day is fun and all, but you know what's even more fun? Fucking your girlfriend.What a shame the universe said no.Female! UnderFell Sans/Gender-Neutral Reader with AFAB.:)
Relationships: Sans (Undertale)/Reader
Comments: 2
Kudos: 42





	Spilled Bath Water

**Author's Note:**

  * For [orions_doubt](https://archiveofourown.org/users/orions_doubt/gifts).



> Hey guys! This is a gift fic for the lovely Orion's_Doubt my wonderful Co-Author for the new "Glitter Bombs and Regret" fanfiction which I recommend checking out!
> 
> Instead of the Normal UnderFell Sans x Reader I made Red a girl! Reader is mostly gender neutral but with afab.
> 
> Love y'all and be sure to check out their work!

* * *

The lights were low, and you gazed at the sky. The stars did their silly little dance and you frowned. It was the holiday of love, and you couldn't do anything.

Why?

Oh your period had started, you groaned. Why? You could've been chilling with your ass of a girlfriend, but your body had deemed it impossible. You flopped to your side and rolled across the grassy floor towards the door to your house.

Legs were pointless and you didn't exactly wanna get up. You dragged your body towards the door and managed to open it without getting off the ground. You pulled yourself inside and lay on the ground in there, life was meaningless and death eminent.

"uhh babe?" A sneakered foot nudged your side and you startled rolling to the side. No one was supposed to be here, especially not your girlfriend.

"What the fuck are you doing here. I told you I was sick." You coughed for good measure, and your girlfriend narrowed her eye sockets at you.

"uh huh..." Her golden tooth glinted in the light, and you found your gaze attracted to it. God, she was incredible.  
"what a shame."

"Yep, now why don't you leave," you sniffed for good measure making a deal of it being hard to do. "Before you catch it!"

"sweetheart, ya do know monster's can't catch human diseases right?" She shuffled slightly, eyelights narrowed slightly and you scowled. Why was she being so damn difficult???

"Yeah but I'm tiiiiiiired, and just wanna lay here forever~" You tossed a hand over your eye and blinked wearily at her, really hamming it up.

She shrugged. "kay then," and with that she dropped on top of you, pinning your body to the ground, her ribcage was pressed against your stomach. And you found yourself gasping for air in surprise. Red chuckled against the carpet, her voice huskier sounding than normal and you flushed at the sound of it. It wasn't fair!

You shoved at Red and growled when she didn't budge, "You have five seconds to get off of me or we are breaking up." You threatened, not that you'd actually do something like that, you were grumpy not a heartless bitch.

"nope." Came the muffled reply and you groaned.

"Please? I really want some food to eat."

Red shoved a hand in her pocket before giving you a bag of Hershey Kisses. "eat these. it's that time of year anyways."

Awww what a sweetheart, getting you chocolate on Valentine's day. You were flattered. "Gee thanks, guess that takeout can wait, I have to put up with your multitude of kisses apparently. You huffed sarcastically and Red chuckled.

"ya sure about that babe?" She closed her sockets and you eyed her suspiciously (Red sus). She had made herself comfortable on the floor, draped dramatically over your stomach. And was acting really cuddly. Also when did her bones feel so warm?

"Yeah. I was gonna order a pizza when I came in, but my legs were broken and my phone was too far away." Your girlfriend sat up slightly and you pointed to your phone, which sat less than three feet away resting on a table. Red rolled her eyes and with a flick of her finger you were smacked in the head with your phone.

"Thanks."

"no problem." Came the muffled reply and you patted at her skull.

You tapped at your phone for a few more minutes, placing an order for some Monster Friendly Pizza© and paying for it. You soon turned it off though and lay back down on the floor eyes closing. Your girlfriend was already asleep and you knew that you'd soon follow.  
And it wasn't gonna be very fast that the pizza dude got there, at LEAST thirty minutes. You had time for a short nap.  
  
  


"babe, sweetheart, demon from hell itself, doll, kitten. c'mon wake up." Someone was shaking your arm slightly and you whined and rolled over, burying yourself into to couch further.

"Nooo" you swatted sleepily at the entity tugging your arm and you flinched awake when a swat landed on your ass.  
"What the hell dude?!" You spat out, a glare decorating your face. Red laughed and you rolled your eyes. You were also on the couch instead of the floor now.

"ugh. not even a thanks for my efforts? i see how it is." Red rolled her eyelights and you snorted. "anyways foods here, so get tha fuck up."

You reluctantly sat up, and stretched. You still were fairly sleepy, the coils of sleep reluctant to release you. Your girlfriend chuckled and offered you a boney hand. You chose not to take it and got yourself up without it and into the kitchen without any assistance.

The pizza box was laying on the counter, the image of the classic MTT logo resting on the cover. You felt a slight cramp of hunger and not bothering to wait for Red you went ahead and snitched a slice. Motherfucker could deal with this as pay back for waking you up.

You eagerly devoured the slice and picked up another one but you realized Red had never come back with you. Another minute passed before you decided to call out for her.   
"Uh Red? Babe? Where'd the hell you go?" You heard a faint thump down the hallway near where your room was. You debated about going to see what she was doing, but decided against it with a shrug. Red probably wouldn't want you to bother her over something stupid like that.

Another minute passed and you heard a small * _VoIP_ * and Red was now a slightly sweaty mess in your kitchen, a ways away from where you were standing. You were eating a third piece of pizza and she eyed you.

"enjoying yourself doll?" You hummed and made a big deal about taking another bite. Red watched you for another minute before turning away and grabbing a slice for herself.  
Red opened her large maw and maintained eye contact and dropped the slice into her mouth. She chewed for a few seconds before swallowing it down with a soft groan.

You felt your cheeks flush at the noise and you felt even angrier at your body than before. Why. Did. It. Have. To. Happen. Tonight?

Red smirked, and shifted to allow you a gap so you could see her summoned ecto-breasts. You flushed harder and lowered your eyes as not to give into temptation. "I told you Red, I'm sick and don't really feel up to d-doing anything." You forced out, stumbling over your words when she teleported to behind you and draped herself over your back. Her breasts were pressed into you and you shivered slightly.

"tha' so?" Red rubbed a hand along your arm, her sharp phalanges faintly scratching at you. "why dontcha just," her voice dropped to a husky murmur, and you were fighting yourself internally. "let me take care of ya dollface, i'll do the best job of it too." She nuzzled into your neck and you whimpered slightly, hormones raging internally.

Red began leading you out of the kitchen, and you came along with her in a daze. Why were you so against this again? You weren't entirely sure, just that you were now in your bedroom and Red laying you back onto the bed.

"alright sweetheart, i'm just gonna out these on ya and we can get down to caring for ya." She tugged off your shirt, and grinned darkly when she realized you had forgone a bra. The shirt was tossed to the side landing God knows where and she reached into your bedside table searching for something.

Click!

Handcuffs were now clasped around your wrists and tied to the headboard of your bed. You tugged at them for no reason other than fun and Red swatted at your arms.  
"alright babe?" You nodded dazedly. "let's get down to business then!"

Red placed a hand on your breasts squeezing them tightly, and you gasped and the feeling. Damn you felt so sensitive, why couldn't you remember? Red laughed, the sound low and promising and you gave a quiet yelp when she twisted your nipples harshly.

"Hey! Slow down some," you forced out and Red pulled back with a surprised look.

"why tha fuck are you so damn sensitive. you've never been like this before." Red's hand was still messing with your breasts, massaging and fondling them at a slightly less bruising hold.

Why were you so sensitive...?

Oh!

Shit.

"I-I just remembered we can't do this Red. I'm so sorry~" Red narrowed her eyes and her mouth turned into a scowl so fast you had whiplash.

"why?" She leaned in close to your face, "is this." Red swiped a tongue across your lip. "not doin it for ya?" She leaned in kissing you harshly, a hand threading it's way into your messy hair.

You moaned into the kiss, sucking softly at the intruding tongue. Red's tongue was all over the interior of your mouth, and you eagerly took it.  
She pulled back suddenly and you found yourself whining for more. But you had to stop this now.

"Babe, we can't do this right now, I-I'm sorry." Red scowled and you didn't miss the flash of hurt in her sockets.

"and why t'fuck not?" She snarled, the hand in your hair tugging it backwards slightly, placing your neck on display.

"Cause I'm on my period! Dammit!" You gasped out as her teeth grazed your neck gently.

She chuckled and your blood ran cold. You felt her teeth open and she bit at your neck. You gave a stuttered shriek as her shark like teeth dug into your neck, it was hard enough that it began bleeding, but gentle enough that you had no risk of dying. She pulled back and lathed her tongue all over it. Covering it in a layer of red saliva.

"you think i care about something like that?" She eyed you and the fresh bite mark on your neck. "just blood, and i'm not gonna get grossed out by something like that...that why you've been so sensitive?"

You whimpered and nodded, and Red's look softened. "poor baby." She purred and you nodded eagerly. In actuality it was pretty bad.

"yeah?" Red's hand was snaking it's way down to your shorts and you gasped when she touched your thighs. Red smirked and pulled off your shorts and lifted a hand to show you the goopy mixture decorating her phalanges. Blood and arousal were mixed together and you knew your shorts and underwear were both ruined.

Red's phalange swiped along your slit and you jerked hard in your bonds and Red gave you a surprised look. "damn. you really are sensitive."

She landed on your clit with practiced ease and you found yourself moaning and slightly embarrassed at the state you were in. Her phalanges were circling your clit with practiced ease, and you were shaking slightly.

Red's smirk was almost terrifyingly large, and she winked at you and stuck a phalange in your hole. You jerked hard against the cuffs and you whimpered. Red seemed impressed and terrifyingly overwhelmed by the power she had over you.

You had nearly cum from just that and you whimpered when she began curling her finger twisting it tightly. You could feel everything and it was overwhelming you very quickly. She found your g-spot with no difficulty and you felt tears spring to your eyes. It felt so good, and Red's other hand was fondling your breasts again.

She added another phalange and you found yourself riding her hand eagerly. Red laughed at the display and increased her speed slightly. That was all you needed and you gasped as you clenched around her phalanges. You moaned and Red continued her movements through your orgasm. When the passing waves had gone on she removed her hand and reached up to release your wrists.

"W-wait! What are you doing?" You asked, rubbing at your released wrists.

"doll, you're so sensitive and i wouldn't do that to you...yet. so let's get ya cleaned up and go watch a shitty movie." You reluctantly agreed as you suddenly felt exhausted and you didn't want to become any more over stimulated than before. 

Red scooped you up and dragged you to the bathroom, laughing when you nuzzled into her breasts. She turned the bath on and began dumping random amounts of bubble bath into it.

You watched as the water slowly rose, and Red turned back to you. She lifter your chin up, examining the bite on your neck before giving you short and sweet kiss.

"ya know you could've just told me..." Red trailed off as you pulled her into a hug.

"It's messy human junk, and I didn't wanna do that to you. I love you too much for that." You clutched to her T-shirt and blew a kiss up at her blushing face.

"love ya too sweetheart," and you giggled softly when her eyelights turned into small red hearts.

"Good...." You bit your lip before asking the question that was dying to spill out. "What were you doing before you came into the kitchen?"

Red flushed and ducked away murmuring something under her breath and you couldn't catch what she said.

"Excuse??"

"trying to find the damn handcuffs. they weren't in the drawer earlier this evening. "

You frowned skepticism at that, but you'd probably find out eventually. You opened your mouth to push her some more, but a flash of wet against your foot had you in a panic.

"OH SHIT. THE BATH!!!"


End file.
